My Apple 27” Thunderbolt Display was flickering on and off intermittently (running on my M1 MacBook Air via a Apple USB C/Thunderbolt Adapter). Turns out it was the integrated Thunderbolt cable – I’ve connected it using a seperate cable and it now works perfectly (the display has a separate Thunderbolt port you can use).

Eventually I may try to replace the cable properly but it’s a fairly involved job… (thanks Apple!).